In the play "Macbeth" by William Shakespeare, the quote reflects the profound impact of guilt on Macbeth after he murders King Duncan. The voice he imagines signifies his loss of peace and innocence, indicating that he has disrupted the natural order of life, particularly the restorative power of sleep. Sleep is portrayed as essential for both physical and mental well-being, illustrating how the act of murder has not only led to his moral downfall but has also stripped away his tranquility.

This passage emphasizes sleep's role as a fundamental aspect of human existence, providing relief from the stresses of life and serving as a restorative time for the mind and body. By stating that Macbeth "does murder sleep," Shakespeare highlights the irreversible consequences of Macbeth's ambition, suggesting that once he has committed regicide, he can no longer enjoy the simple, restorative pleasures that sleep offers. The weight of his actions haunts him, marking a profound transformation in his character.